Hydrocarbon conversion processes employing perovskite catalysts

ABSTRACT

A high surface area perovskite catalyst comprises a perovskite containing at least one transition metal composited with a spinel coated metal oxide support. The catalyst is prepared by forming a surface spinel on a metal oxide and subsequently co-impregnating or co-depositing the appropriate perovskite precursor component on the spinel coated metal oxide, followed by calcination at a temperature of at least 540° C. A preferred catalyst is LaCoO 3  supported on a spinel covered alumina.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 676,511, filed Apr. 13, 1976,now U.S. Pat. No. 4,055,513.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel perovskite catalysts, methods fortheir preparation and uses thereof in hydrocarbon conversion processes.

2. Description of the Prior Art

It is known that perovskites can be used as hydrocarbon conversioncatalysts (see, for example, U.S. Pat. Nos. 3,595,809; 3,450,789;3,780,126; and U.K. Pat. No. 1,352,995). The conventional method ofpreparing pure perovskites has been a repetition of the steps of hightemperature fusion of a mixture of metal oxides and ball milling toreduce the fused mass to submicron size particles and to expose freshunreacted oxide for the repeated fusion step. Due to the repeated hightemperature treatments which induce melting and sintering, the thusprepared perovskites have relatively low surface areas, typically fromabout 1 to about 20 m² /g (BET).

U.S. Pat. No. 3,897,367 discloses perovskite-type compounds which may beemployed as catalyst in the form of coatings on suitable refractorysupports.

For use as catalysts, especially for use as hydrocarbon conversioncatalysts, it is desirable to obtain high surface area perovskites.Attempts to produce supported high surface area perovskite catalysts bysimple impregnation techniques on alumina gel resulted in a supportedspinel and not in the desired supported perovskite.

It has now been found that high surface area perovskite catalysts can beproduced by the preparation methods of the present invention.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided a supportedperovskite catalyst which comprises a perovskite containing at least onetransition metal composited with a support comprising a metal oxide anda spinel on the surface of said metal oxide.

Furthermore, in accordance with the invention, there is also provided aprocess for preparing a supported perovskite catalyst which comprises(a) treating a metal oxide with at least one metal component such thatthe algebraic sum of the ionic charges of the metal of said metal oxideand the metal of said metal component corresponds to the algebraic sumof cations required for spinel formation; (b) calcining the treatedmetal oxide resulting from step (a), thereby producing a spinel on atleast a portion of the surface of said treated metal oxide; (c) treatingthe calcined metal oxide having said surface spinel thereon, resultingfrom step (b), with perovskite precursor metal components, saidprecursor metal components comprising at least one transition metalcomponent, (d) calcining at a temperature of at least 540° C. theperovskite precursor-treated material resulting from step (c) to convertsaid perovskite precursors to a perovskite and thereby produce asupported perovskite catalyst.

The term "transition metal" is intended herein to designate elementshaving atomic numbers ranging from 21 through 30, from 39 through 48,from 57 through 80 and from 89 through 92.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The supported perovskite catalyst of the present invention comprises aperovskite comprising at least one transition metal composited with asupport comprising a metal oxide and a spinel on the surface of themetal oxide. The term "perovskite" is intended herein to designate metaloxides having the ideal and non-ideal perovskite-type crystallinestructure. The ideal perovskite crystalline structure is defined by theempirical formula ABO₃ in which A and B are cations of two differentmetals and in which the A cation is coordinated to twelve oxygen atomswhile the B cation occupies octahedral sites and is coordinated to sixoxygen atoms. The ideal perovskite structure is cubic, however, fewcompounds have this ideal structure. The term "perovskite" structuredraws its name from the mineral perovskite (CaTiO₃) which was firstthought to have a cubic structure that has now been determined to beorthorhombic. For example, the compound LaMnO₃ has the ideal structurewhile some complex oxides, such as La₀.7 Sr₀.3 MnO₃ which exhibit avariety of other structures are still classed as perovskite-typestructures. A more complete description of the perovskite-type structureis found in Structural Inorganic Chemistry, A. F. Wells, 3rd Edition,Oxford, the Clarendon Press, 1962, pages 494 to 499. In general thealgebraic sum of the ionic charges of the two or more metals (cations)of the perovskite equals plus six.

The term "spinel" is intended herein to designate a binary oxide havingthe normal spinel structure or the inverse spinel structure. The normalspinel may be represented by the formula MY₂ O₄ wherein M and Y arecations of different metals. The inverse spinel may be represented bythe formula Y(XY)O₄ wherein Y and X are cations of different metals. Thesum of the cationic charges of the spinel equals 8. The crystallographicstructures of the normal and inverse spinels are given in the abovementioned A. F. Wells, Structural Inorganic Chemistry, pp. 487-488.

Suitable metal oxide components of the catalysts include Al₂ O₃ ; MgO;TiO₂ ; Zr₂ O; Hf₂ O; WO₃ and mixtures thereof.

The supported perovskite catalysts of the invention are prepared by thefollowing steps: a metal oxide is treated with at least one metalcomponent such that the sum of the ionic charges of the metal of themetal oxide and of the metal of the metal component (or metals of themetal components) satisfy the requirement for spinel formation, that is,that the sum equals 8 and that the ionic radii of the metals satisfy therequirements for spinel formation of the normal spinel type or of theinverse spinel type structure. The metal oxide utilized may be a porousmetal oxide or a porous metal oxide gel. The surface area of theinitially utilized metal oxide will generally range from about 50 m² /gto about 250 m² /g. Suitable metal oxides include Al₂ O₃ ; MgO; TiO₂ ;ZrO₂ ; HfO₂ ; WO₃ and mixtures thereof.

Suitable metal components for the treatment of the metal oxide arecompounds having cations that will complement the cation of the metaloxide to satisfy the rule of spinel formation. By way of example,suitable metal components include metals, metal oxides, metalhydroxides, metal salts of Mg, Fe Co, Ni, Mn, Zn, Ti, Sn, Cu, Cr, etc.

The treatment of the metal oxide is generally carried out by utilizing asolution of the desired metal component to impregnate or deposit themetal component on the metal oxide. The treated metal oxide issubsequently calcined at a temperature ranging from about 500° to about1000° C. Calcination of the treated metal oxide produces a surfacespinel on at least a portion of the metal oxide. If desired, the metalcomponent can be used in a sufficient amount in the treatment to coverall of the surface of the metal oxide. The metal oxide having thesurface spinel thereon is subsequently treated with perovskite precursormetal components. This treatment may be effected by co-impregnation orco-deposition of the appropriate perovskite precursor metal componentson the metal oxide having the surface spinel. The perovskite precursorsare components which contain cations, the sum of which will equal plussix and which cations have ratios of ionic radii that satisfy therequirements for perovskite formation. The requirements for perovskiteformation are given in Structure, Properties and Preparation ofPerovskite-type Compounds by Francis S. Galasso, Pergamon Press, Oxford,1969. Suitable perovskite precursor components include metals, metaloxides, metal hydroxides, metal salts and mixtures thereof of metalshaving valences ranging from 1 to 5, such as silver, niobium, cesium,potassium, rubidium, barium, iron, lead, strontium, lanthanum, cobalt,aluminum, lead and the like, and mixtures thereof. The perovskiteprecursor components used to prepare the catalysts of the presentinvention must comprise at least one transition metal component.Subsequently, the perovskite precursor treated material is calcined at atemperature of at least 540° C., generally at a temperature ranging fromabout 540° C. to about 1040° C., for example, at about 600° C. toproduce a perovskite on the spinel coated metal oxide. The finalsupported perovskite catalysts will have a surface area of at least 65m² /g, preferably a surface area ranging from about 65 m² /g to about250 m² /g. Additional catalytic active metal components may becomposited with the supported perovskite catalyst.

The novel catalysts of the invention can be used in a number ofhydrocarbon conversion processes and hydrocarbon treating processes suchas cracking, reforming, hydrogenation, oxidation, dehydrocyclation,isomerization, hydrocracking, hydrodesulfurization, denitrogenation,demetallization, etc.

The following examples are presented to illustrate the invention.

EXAMPLE 1

A gamma alumina gel having a surface area of about 185 m² /g (50 gthereof) was impregnated with Mg(NO₃)₂. The impregnated material wascalcined at 540° C. thereby producing a surface coating of MgAl₂ O₄ (aspinel) on the alumina. The resulting material was re-impregnated withan equi-molar solution of La(NO₃)₃.6H₂ O and Co(NO₃)₂.6H₂ O andsubsequently calcined at the temperature of 600° C. The calcinedmaterial had a surface coating of the perovskite, LaCoO₃, as identifiedby ESCA (Electron Spectrometry for Chemical Analysis).

The color of the preparation was black. When the same gamma alumina wastreated directly with the same equi-molar solutions of La(NO₃)₃.6H₂ Oand Co(NO₃)₂.6H₂ O and subsequently calcined at 600° C., the color ofthe preparation was 50% blue and 50% black. The blue color wasattributed to the formation of CoAl₂ O₄ (as spinel) and ESCAidentification was negative for the perovskite LaCoO₃. These resultsindicate the necessity of first forming a spinel on the metal oxidesupport prior to treating it with a perovskite precursor to prepare asupported perovskite.

EXAMPLE 2

The supported LaCoO₃ perovskite catalyst prepared by the method of theinvention given in Example 1 was tested as a hydrocarbon conversioncatalyst. The tests were conducted as follows: hydrogen carrier gas isbubbled through a gas scrubbing tower containing an appropriate purehydrogen feed, entraining vapors of the feed. This gas stream thencontacted the catalyst contained in a reactor maintained at the desiredtemperature in a sandbath, wherein conversion of the feed was effected.Reaction products were determined by sampling the effluent downstream ofthe reactor and analyzing and identifying the product mixture by meansof gas chromatography. The operation was carried out at 0 psig totalpressure and hydrocarbon space velocities varying from 0.5 to 3.0W/Hr./W. The temperature of operation varied from 150° C. to 500° C.

The results of the tests are summarized in Table I.

                                      TABLE I                                     __________________________________________________________________________    HYDROCARBON CONVERSION WITH SUPPORTED LaCoO.sub.3                             Product Analyses (Gas Chromatographic Area %)                                           Cyclohexane                                                                          n-Heptane                                                                           Cumene                                                                              Methylcyclopentane                               Component Conversion                                                                           Conversion                                                                          Conversion                                                                          Conversion                                       __________________________________________________________________________    2,3-DMB/2-MP                                                                            5.6    0.0   0.0   0.0                                              n-Hexane  7.0    1.8   3.6   2.2                                              Methylcyclopentane                                                                      0.0    64.0  15.8  60.0                                             Cyclohexane                                                                             66.0   28.4  23.4  32.8                                             Heptanes  21.5   0.0   12.4  1.2                                              Benzene   0.0    3.1   1.8   1.9                                              Toluene   0.0    0.0   0.1   0.0                                              Cumene    0.0    0.0   0.0   0.0                                              __________________________________________________________________________

EXAMPLE 3

A supported LaCoO₃ pervoskite was prepared as follows. Fifty grams ofspinel treated alumina were weighed. The spinel treated alumina wasobtained by treating alumina with Mg(NO₃)₂ and calcining it to form amonolayer of MgO which formed MgAl₂ O₄. A solution of 20.16 gLa(NO₃)₃.6H₂ O and 11.62 g Co(CH₃ CO₂)₂.4H₂ O was made by dissolving in25 cc distilled water by heating and stirring. When the materials weredissolved, the volume of solution was brought up to 50 cc, stirred andthen the solution was added to the support by the method of incipientwetness. The solids were predried for 2 hours at 130° C. and calcined at1000° C. to yield a supported LaCoO₃ perovskite.

EXAMPLE 4

A supported LaCrO₃ was prepared utilizing the identical procedure usedin Example 3 and using 50.00 g spinel treated alumina (the same as theone used in Example 3), 20.20 g La(NO₃)₃.6H₂ O and 18.63 g Cr(NO₃)₃.9H₂O. The solids were predried 1 hour at 130° C. The sample was split andone part was fired at 600° C. and the remainder at 1000° C. to yield asupported LaCrO₃ perovskite.

EXAMPLE 5

A supported SrSnO₃ was prepared as follows. Fifty grams of the samespinel treated alumina (as the one utilized in Example 3) were weighed.24.28 g of Sr(OH)₂.8H₂ O and 20.60 g SnCl₂ were dissolved in 25 cc ofconcentrated HCl with heating and stirring. When the materials weredissolved, the volume of solution was brought up to 50 cc by theaddition of concentrated HCl. The resulting solution was added to thesupport by the method of incipient wetness. The solids were predried atambient conditions and then calcined at 800° C. to yield a supportedSrSnO₃.

EXAMPLE 6

The supported perovskites prepared in accordance with Examples 3 to 5were tested for catalytic activity. The results of these tests aresummarized in Tables II to IV.

As can be seen from Table IV, SrSnO₃ on spinel-treated alumina, that is,a perovskite which did not contain at least one transition metal, didnot have any significant catalytic activity according to the comparativetests utilized.

                                      TABLE II                                    __________________________________________________________________________    LaCrO.sub.3 ON SPINEL TREATED ALUMINA (CALCINED AT 600° C),            S.A.=133 M.sup.2 /G.                                                                    Cyclohexane Dehydrogenation                                                                  Methylcyclopentane Reforming                                                                  N-Hexane Isomerization               Reaction  to Make Benzene                                                                              to Make Benzene to Make Hexane Isomers               Activity  Initial                                                                              Lined-Out                                                                             Initial Lined-Out                                                                             Initial                                                                             Lined-Out                      __________________________________________________________________________    At                                                                            Time (Min.)                                                                             5      297     5       239     7     229                            Wt. % Conversion                                                                        29     18      5       10      5     4                              % Selectivity                                                                 to Desired                                                                              13     97      18      13      69    85                             Product                                                                       Temp. ° C                                                                        495            495             150                                  W/Hr/W    0.5            1.5             1.5                                  __________________________________________________________________________

                                      TABLE III                                   __________________________________________________________________________    LaCrO.sub.3 ON SPINEL TREATED ALUMINA (CALCINED AT 1000° C),           S.A.=94 M.sup.2 /G                                                                      Cyclohexane Dehydrogenation                                                                  Methylcyclopentane Reforming                                                                  N-Hexane Isomerization               Reaction  to Make Benzene                                                                              to Make Benzene to Make Hexane Isomers               Activity  Initial                                                                              Lined-Out                                                                             Initial LIned-Out                                                                             Initial                                                                             Lined-Out                      __________________________________________________________________________    at                                                                            Time (Min.)                                                                             5      300     5       186     5     271                            Wt. % Conversion                                                                        31     14      34      7       4     6                              % Selectivity to                                                                        12     93      6       14      77    87                             Desired Product                                                               Temp. ° C                                                                        495            495             150                                  W/Hr/W    0.5            1.5             1.5                                  __________________________________________________________________________

                                      TABLE IV                                    __________________________________________________________________________    SrSnO.sub.3 ON SPINEL TREATED ALUMINA (CALCINED AT 800° C),            S.A.=106 M.sup.2 /G                                                                     Cyclohexane Dehydrogenation                                                                  Methylcyclopentane Reforming                                                                  N-Hexane Isomerization               Reaction  to Make Benzene                                                                              to Make Benzene to Make Hexane Isomers               Activity  Initial                                                                              Lined-Out                                                                             Initial LIned-Out                                                                             Initial                                                                             Lined-Out                      __________________________________________________________________________    at                                                                            Time (Min.)                                                                             5      202     5       137     5     147                            Wt. % Conversion                                                                        1      1       38      2       3     3                              % Selectivity to                                                              Desired Product                                                                         0      0       4       36      87    94                             Temp. ° C                                                                        495            495             150                                  W/Hr/W    0.5            1.5             1.5                                  __________________________________________________________________________

EXAMPLE 7

A number of supported perovskites were tested for their activity ascatalyst for various hydrocarbon conversion reactions. Results of thesetests are summarized in Tables VI to XXI.

The experimental procedures used in experiments reported in Tables VI toXXI were as follows.

A controlled flow of carrier gas, either hydrogen or helium, is admittedto a gas scrubbing tower containing the appropriate pure hydrocarbon.The flowing gas entrains vapors of the hydrocarbon and serves as thefeed supply to the reactor. Knowing the temperature of the hydrocarbonin the gas tower determines the vapor pressure of the hydrocarbon. Aknowledge of the vapor pressure of the hydrocarbon, the absolute flow ofthe carrier gas under standard conditions, and the barometric pressureenables the hydrocarbon feed rate to be calculated.

The gas exiting the gas scrubbing tower is a mixture of the hydrocarbonvapor and the carrier gas. This gas mixture is transported throughheated lines to a reactor containing the catalyst to be tested whereinit contacts the catalyst and then exits the reactor. The product gasmixture is usually a complicated mixture of various hydrocarbons as wellas the carrier gas and is transported from the reactor to a samplingpoint through heated lines. Heated lines are necessary to preventcondensation.

The product is sampled via a port protected with a septum. A syringe isinjected through the septum and the sample withdrawn. The sample isinjected into a gas chromatograph and analyzed as to its components andtheir relative percentages. Once feed is introduced to the catalyst,samples are taken approximately every 60 minutes over a 5 hour testperiod.

The unit is operated at atmospheric pressure (0 psig). Although thisdoes not duplicate many commercial processes which are usually operatedunder pressure, this pressure is convenient for a laboratorydetermination of catalyst activity and low pressure is a more severecondition for catalyst testing than high pressure; high pressures ofhydrogen being used commercially to prevent catalyst deactivation.

The catalysts tested are given a pretreatment with hydrogen for twohours before admitting feed to the system.

The experimental conditions utilized in the tests reported in Tables VIto XXI are summarized in Table V.

                  TABLE V                                                         ______________________________________                                        Feedstock (Pure)                                                                           Temp. ° C.                                                                       Carrier Gas                                                                              W/Hr/W*                                     ______________________________________                                        Cyclohexane  494       H.sub.2    1                                           Methyl cyclopentane                                                                        494       H.sub.2    3                                           n-heptane    494       H.sub.2    1                                           n-hexane     150       He         3                                           Benzene      150       H.sub.2    2                                           ______________________________________                                         *These values vary somewhat depending on the bulk density of the catalyst     charged. Catalyst charges are 1 cc in all cases of 20-40 mesh material.  

                  TABLE VI                                                        ______________________________________                                        CYCLOHEXANE CONVERSION TO BENZENE                                             Catalyzed by LaCrO.sub.3 on Spinel                                            Treated Alumina (calcined at 1000° C)                                  Conditions: 495° C, 0 psig                                             ______________________________________                                        Time (Min)      5      175    215  255  300                                   Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           26.76  0.07   0    0.03 0.04                                  Methylcyclopentane                                                                            0      0.12   0.16 0.10 0.10                                  Cyclohexane (feed)                                                                            69.17  84.86  84.76                                                                              85.28                                                                              85.54                                 Benzene         3.65   14.50  14.02                                                                              12.99                                                                              13.50                                 Other           0.42   0.45   1.06 1.60 0.82                                  Wt. % Conversion                                                                              30.83  15.14  15.24                                                                              14.72                                                                              14.46                                 Selectivity to benzene                                                                        11.8   95.8   92.0 88.2 93.4                                  ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                        CYCLOHEXANE CONVERSION TO BENZENE                                             Catalyzed by LaCrO .sub.3 on Spinel                                           Treated Alumina (Calcined at 600° C)                                   Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)     5      170    212  256  297                                   Product (Wt. %)                                                               2,3-dimethyl butane                                                           and 2 methylpentane                                                                           24.90  0      0.03 0.05 0                                     Methylcyclopentane                                                                            0      0.12   0.14 0.13 0.09                                  Cyclohexane (feed)                                                                            70.66  84.34  85.45                                                                              83.59                                                                              82.17                                 Benzene         3.73   15.37  14.02                                                                              15.28                                                                              17.26                                 Other           0.71   0.17   0.36 0.95 0.48                                  Wt. % Conversion                                                                              29.34  15.66  14.55                                                                              16.41                                                                              17.83                                 Selectivity to Benzene                                                                        12.7   98.1   96.4 93.1 96.8                                  ______________________________________                                    

                  TABLE VIII                                                      ______________________________________                                        CYCLOHEXANE CONVERSION TO BENZENE                                             Catalyzed by SrSnO.sub.3 on Spinel Treated Alumina                            Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)        5       102     202                                        Product (Wt. %)                                                               Cyclohexane        99.21   99.14   99.12                                      Benzene            0       0       0                                          Other              0.79    0.86    0.88                                       Wt. % Conversion   0.79    0.86    0.88                                       % Selectivity to Benzene                                                                         0.0     0.0     0.0                                        ______________________________________                                    

                  TABLE IX                                                        ______________________________________                                        METHYLCYCLOPENTANE CONVERSION                                                 TO HEXANE ISOMERS                                                             Catalyzed by CaThO.sub.3 on Spinel Treated Alumina                            Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)     5      86     127  183  248                                   Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           32.97  8.25   0    0    0                                     3-methylpentane 21.8   2.80   0    0    0                                     n-hexane        1.99   1.19   0    0    0.11                                  Methylcyclopentane                                                                            60.62  84.73  96.96                                                                              96.84                                                                              97.45                                 (feed)                                                                        Cyclohexane     1.19   1.39   1.41 1.38 1.12                                  Other           1.05   1.64   1.63 1.78 1.32                                  Wt. % Conversion                                                                              39.38  15.27  3.04 3.16 2.55                                  % Selectivity to                                                                              97.3   89.3   46.4 43.7 48.2                                  C.sub.6 Isomers                                                               ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        METHYLCYCLOPENTANE CONVERSION TO BENZENE                                      Catalyzed by LaCrO.sub.3 on Spinel                                            Treated Alumina (Calcined at 600° C)                                   Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)    5      51     132  173  238  282                               Product (wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                          0      1.02   0.74 1.19 0.79 0.51                              Methyl cyclopentane                                                                          95.39  92.43  89.95                                                                              90.34                                                                              90.47                                                                              92.54                             Cyclohexane    2.30   3.93   4.54 4.62 4.54 4.48                              Benzene        0.83   0.92   1.14 0.99 1.28 0.89                              Other          1.48   4.10   3.63 2.86 2.92 1.58                              Wt. % Conversion                                                                             4.61   7.57   10.05                                                                              9.66 9.53 7.46                              % Selectivity  18.0   12.2   11.3 10.2 13.4 11.9                              to Benzene                                                                    ______________________________________                                    

                  TABLE XI                                                        ______________________________________                                        METHYLCYCLOPENTANE CONVERSION TO BENZENE                                      Catalyzed by LaCrO.sub.3 on Spinel                                            Treated Alumina (Calcined at 1000°)                                    Conditions: 495° C, 0 psig                                             ______________________________________                                        Time (Min.)        5      90     139  186                                     Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                              28.32  0.52   0.51 0.39                                    Methyl cyclopentane                                                                              65.76  85.67  92.48                                                                              93.32                                   Cyclohexane        2.57   4.27   3.86 3.55                                    Benzene            2.03   1.36   1.30 0.90                                    Other              1.32   8.18   1.85 1.84                                    Wt. % Conversion   34.24  14.33  7.52 6.68                                    % Selectivity      5.9    9.5    17.3 13.5                                    to Benzene                                                                    ______________________________________                                    

                  TABLE XII                                                       ______________________________________                                        n-HEPTANE CONVERSION TO HEXANE ISOMERS                                        Catalyzed by LaCrO.sub.3 on Spinel                                            Treated Alumina (calcined at 600° C)                                   Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)     5      46     93   139  288                                   Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           61.20  40.59  0    0.07 0.10                                  Methylcyclopentane                                                                            9.16   7.29   8.43 3.63 4.43                                  Cyclohexane     1.87   1.80   2.38 0.41 0.64                                  n-heptane (feed)                                                                              27.07  48.16  82.52                                                                              91.70                                                                              89.10                                 Other           0.70   2.16   6.67 4.19 5.73                                  Wt. % Conversion                                                                              72.93  51.84  17.48                                                                              8.30 10.90                                 % Selectivity to C.sub.6                                                      Isomers         99.0   95.8   61.8 49.5 47.4                                  ______________________________________                                    

                  TABLE XIII                                                      ______________________________________                                        n-HEPTANE CONVERSION TO HEXANE ISOMERS                                        Catalyzed by CaThO.sub.3 on Spinel Treated Alumina                            Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)     6      137    182  289  298                                   Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           74.03  20.82  0    0    0                                     Methylcyclopentane                                                                            3.64   5.76   0    0.64 0.67                                  Cyclohexane     2.03   2.12   0.29 0    0.22                                  n-hexane        0      0      0    0.23 0.23                                  n-heptane (feed)                                                                              20.21  69.66  97.95                                                                              97.63                                                                              98.57                                 Other           0.09   1.64   1.76 1.50 0.31                                  Wt. % Conversion                                                                              79.79  30.34  2.05 2.37 1.43                                  % Selectivity to                                                              C.sub.6 Isomers 99.9   94.6   14.1 36.7 78.3                                  ______________________________________                                    

                  TABLE XIV                                                       ______________________________________                                        n-HEPTANE CONVERSION TO HEXANE ISOMERS                                        Catalyzed by AgNbO.sub.3 on Spinel Treated Alumina                            Conditions: 494° C, 0 psig                                             ______________________________________                                        Time (Min.)     6      82     132  178  233                                   Product (Wt. %)                                                               n-hexane        0.40   0      0.26 0.19 0.17                                  Methylcyclopentane                                                                            14.66  0      5.47 4.09 3.40                                  Cyclohexane     2.31   0      0.46 0    0.38                                  n-heptane (feed)                                                                              75.20  85.04  90.25                                                                              91.30                                                                              93.87                                 Methylcyclohexane                                                                             2.00   1.57   0.37 0.80 0                                     Toluene         1.20   0      0.17 0    0                                     Other           4.23   13.39  3.02 3.62 2.18                                  Wt. % conversion                                                                              24.80  14.96  9.75 8.70 6.13                                  Selectivity to C.sub.6                                                                        70.0   0      63.5 49.2 64.4                                  Selectivity to toluene                                                                        4.8    0      1.7  0    0                                     ______________________________________                                    

                  TABLE XV                                                        ______________________________________                                        n-HEXANE ISOMERIZATION                                                        Catalyzed by AgNbO.sub.3 on                                                   Spinel Treated Alumina (S.A. = m.sup.2 /g)                                    Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)    5      85     127  168  213  Avg.                              Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                          54.66  32.25  21.69                                                                              21.87                                                                              18.34                                  3-methylpentane                                                                              0      1.95   0    0    1.98                                   Methylcyclopentane                                                                           2.64   3.02   5.08 4.82 3.00                                   Cyclohexane    0      0      0    0    1.08                                   n-hexane (feed)                                                                              41.71  61.50  72.30                                                                              71.68                                                                              74.89                                  Other          0.99   1.28   0.93 1.63 0.71                                   Wt. % Conversion                                                                             58.29  38.50  27.70                                                                              28.32                                                                              25.11                                                                              35.6                              % Selectivity to                                                              C.sub.6 Isomers                                                                              98.3   96.7   96.6 94.2 97.2 96.6                              ______________________________________                                    

                  TABLE XVI                                                       ______________________________________                                        n-HEXANE ISOMERIZATION                                                        Catalyzed by CaThO.sub.3 on                                                   Spinel Treated Alumina (S.A. = m.sup.2 /g)                                    Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)     5      97     149  266  Avg.                                  Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           37.84  8.61   0.43 0.44                                       3-methylpentane 1.74   1.80   0.45 0.45                                       Methylcyclopentane                                                                            2.38   2.91   2.74 1.76                                       Cyclohexane     0.84   0.67   0.63 0                                          n-hexane (feed) 56.79  84.70  94.67                                                                              96.38                                      Other           0.41   1.31   1.08 0.97                                       Wt. % Conversion                                                                              43.21  15.30  5.33 3.62 16.9                                  % Selectivity to                                                              C.sub.6 Isomers 99.1   91.4   79.7 73.2 85.9                                  ______________________________________                                    

                  TABLE XVII                                                      ______________________________________                                        n-HEXANE ISOMERIZATION                                                        Catalyzed by SrSnO.sub.3 on Spinel                                            Treated Alumina (S.A. = 106 m.sup.2 /g)                                       Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)     5      58     104  147   Avg.                                 Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                           0.49   0.48   0.48 0.46                                       3-methylpentane 0.48   0.48   0.49 0.48                                       Methylcyclopentane                                                                            1.71   1.78   1.85 1.87                                       Cyclohexane     0.15   0.23   0.25 0.24                                       n-hexane (feed) 96.75  96.53  96.70                                                                              96.73                                      Other                                                                         Wt. % Conversion                                                                              3.25   3.47   3.30 3.27  3.32                                 % Selectivity to                                                              C.sub.6 Isomers 87.2   85.6   93.0 93.3  89.8                                 ______________________________________                                    

                  TABLE XVIII                                                     ______________________________________                                        n-HEXANE ISOMERIZATION                                                        Catalyzed by SrZrO.sub.3 (pure material,                                      unsupported, S.A. = 11 m.sup.2 /g)                                            Conditions: 149° C, 0 psig                                             ______________________________________                                        Time (Min.)    5      48     95   138  208  Avg.                              Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                          0.49   0.47   0.45 0.44 0.43                                   3-methylpentane                                                                              0.51   0.49   0.48 0.47 0.46                                   Methylcyclopentane                                                                           1.75   1.77   1.81 1.74 1.74                                   Cyclohexane    0      0      0    0    0                                      n-hexane (feed)                                                                              96.77  96.92  96.92                                                                              96.98                                                                              96.96                                  Other          0.48   0.35   0.34 0.37 0.41                                   Wt. % Conversion                                                                             3.23   3.08   3.08 3.02 3.04 3.09                              % Selectivity to                                                              C.sub.6 Isomers                                                                              85.1   88.6   89.0 87.7 86.5 87.4                              ______________________________________                                    

                  TABLE XIX                                                       ______________________________________                                        BENZENE HYDROGENATION TO HEXANE ISOMERS                                       Catalyzed by LaCrO.sub.3 on Spinel                                            Treated Alumina (Calcined at 600° C)                                   Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)    6      84     127  168  218  259                               Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                          60.66  41.63  19.08                                                                              0    0    0                                 n-hexane       16.15  10.45  8.46 6.15 3.15 2.52                              Methylcyclopentane                                                                           3.94   2.16   2.37 2.18 0.24 0.19                              Cyclohexane    0      0.42   0.45 0.43 0.44 0                                 Benzene (feed) 17.81  44.33  67.35                                                                              91.24                                                                              93.98                                                                              97.29                             Other          1.44   1.01   2.29 0    2.19 0                                 Wt. % Conversion                                                                             82.19  35.67  32.65                                                                              8.76 6.02 2.71                              % Selectivity                                                                 to C.sub.6 Isomers                                                                           98.2   98.2   93.0 100.0                                                                              63.6 100.0                             ______________________________________                                    

                  TABLE XX                                                        ______________________________________                                        HYDROGENATION OF BENZENE TO C.sub.6 ISOMERS                                   Catalyzed by SrSnO.sub.3 on Spinel Treated Alumina                            Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)    6      52     147  190  268  306                               Product (Wt. %)                                                               n-hexane       0.90   0.68   0.82 0.71 0.72 0.61                              Methylcyclopentane                                                                           0.10   0.10   0.14 0.11 0.12 0.09                              Benzene (feed) 98.96  99.17  99.00                                                                              98.86                                                                              98.91                                                                              99.26                             Other          0.04   0.05   0.04 0.32 0.25 0.04                              Wt. % Conversion                                                                             1.04   0.83   1.00 1.14 1.09 0.74                              Selectivity                                                                   to Saturated                                                                  C.sub.6 Isomers                                                                              96.2   94.0   96.0 71.9 77.1 94.6                              ______________________________________                                    

                  TABLE XXI                                                       ______________________________________                                        HYDROGENATION OF BENZENE                                                      Catalyzed by AgNbO.sub.3 on Spinel Treated Alumina                            Conditions: 148° C, 0 psig                                             ______________________________________                                        Time (Min.)        139    180    221  263                                     Product (Wt. %)                                                               2,3-dimethylbutane                                                            and 2-methylpentane                                                                              62.51  35.30  9.53 0                                       Normal hexane      6.41   5.74   5.76 3.03                                    Methylcyclopentane 2.96   1.65   1.76 1.58                                    Cyclohexane        0      0.30   0.27 0.23                                    Benzene            28.09  57.01  82.68                                                                              95.17                                   Other              0.03   0      0    0                                       Wt. % Conversion   71.91  42.99  17.32                                                                              4.83                                    % Selectivity                                                                 to saturated       100.0  100.0  100.0                                                                              100.0                                   C.sub.6 isomers                                                               ______________________________________                                    

The experiments summarized in Tables VI to XXI show that SrSnO₃ which isa perovskite containing no transition metal was inactive for most of thehydrocarbon conversion reactions demonstrated in Tables VIII, XVII andXX.

As can be seen from the tests utilizing SrZrO₃, incorporation of atransition metal, e.g. Zr, improved catalytic activity even thoughSrZrO₃ is a bulk perovskite with low surface area (compare Table XVIIand Table XVIII).

As can be seen from these experiments, the supported perovskites of thepresent invention catalyze a wide variety of hydrocarbon conversionreactions, such as dehydrogenation, as shown in Tables VI and VII;reforming (isomerization and dehydrogenation) as shown in Tables X andXI; selective cracking (loss of methyl group) as shown in Tables XII,XIII and XIV; isomerization as shown in Tables XV and XVI, andhydrogenation as shown in Tables XIX and XXI.

The AgNbO₃ on spinel treated alumina used in the tests of Table XIV,Table XV and Table XXI had a surface area of 96 m² /g. The CaThO₃ onspinel treated alumina used in the tests of Table IX, Table XIII andTable XVI had a surface area of 68 m² /g.

What is claimed is:
 1. A hydrocarbon conversion process conducted underhydrocarbon conversion conditions in the presence of a supportedperovskite catalyst, which catalyst comprises a perovskite comprising atleast one transition metal, and a support comprising a metal oxide and aspinel on the surface of said metal oxide, said spinel being selectedfrom the group consisting of normal spinel and inverse spinel, saidnormal spinel having an empirical formula MY₂ O₄ wherein M and Y in saidnormal spinel formula are cations of different metals and wherein one ofsaid cations of said normal spinel formula is the metal of said metaloxide, said inverse spinel having an empirical formula Y(XY)O₄ wherein Yand X in said inverse spinel formula are cations of different metals,and wherein one of said cations of said inverse spinel formula is ametal of said metal oxide, said supported catalyst having a surface areaof at least 65 m² /g.
 2. The process of claim 1 wherein said metal oxideof said catalyst is a porous metal oxide.
 3. The process of claim 1wherein said metal oxide of said catalyst is selected from the groupconsisting of Al₂ O₃, MgO, TiO₂, ZrO₂, HfO₂, WO₃ and mixtures thereof.4. The process of claim 1 wherein said metal oxide of said catalyst isalumina.
 5. The process of claim 1 wherein said perovskite is an oxideof at least 2 metals and wherein the sum of the ionic charges of themetals of the oxide equals six.
 6. The process of claim 1 wherein saidperovskite is selected from the group consisting of LaCoO₃, LaCrO₃,CaThO₃, AgNbO₃ and SrZrO₃.
 7. The process of claim 1 wherein the cationsof said spinel are selected from the group consisting of Al, Mg, Fe, Co,Ni, Mn, Zn, Ti, Sn, Cu and Cr.
 8. The process of claim 1 wherein saidmetal oxide is alumina and wherein said spinel is MgAl₂ O₄.
 9. Theprocess of claim 1 wherein said perovskite is selected from the groupconsisting of LaCoO₃, LaCrO₃, CaThO₃, AgNbO₃ and SrZrO₃, said perovskitebeing composited with a support comprising alumina and a spinel on thesurface of said alumina, said spinel being MgAl₂ O₄.
 10. The process ofclaim 1 wherein said hydrocarbon conversion process is conducted in theabsence of added oxygen.
 11. The hydrocarbon conversion process of claim1 wherein said conversion process is isomerization.
 12. The hydrocarbonconversion process of claim 1 wherein said conversion process iscracking.
 13. The hydrocarbon conversion process of claim 1 wherein saidconversion is hydrogenation.
 14. The hydrocarbon conversion process ofclaim 1 wherein said conversion process is dehydrogenation.